5 * Exponentiation for abstract groups
7 * (c) 2004 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Header files ------------------------------------------------------*/
33 #include "group-exp.h"
35 /*----- Main code ---------------------------------------------------------*/
37 /* --- @group_stdexp@ --- *
39 * Arguments: @group *g@ = abstract group
40 * @ge *d@ = destination pointer
41 * @ge *x@ = base element
46 * Use: Computes %$d = x^n$% efficiently.
49 void group_stdexp(group
*gg
, ge
*d
, ge
*x
, mp
*n
)
63 if (MP_LEN(n
) < EXP_THRESH
)
71 /* --- @group_stdmexp@ --- *
73 * Arguments: @group *g@ = abstract group
74 * @ge *d@ = destination pointer
75 * @const group_expfactor *f@ = vector of factors
76 * @size_t n@ = number of factors
80 * Use: Computes %$d = g_0^{x_0} g_1^{x_1} \ldots$% efficiently.
86 void group_stdmexp(group
*gg
, ge
*d
, const group_expfactor
*f
, size_t n
)
88 group_expfactor
*ff
= xmalloc(n
* sizeof(group_expfactor
));
91 for (i
= 0; i
< n
; i
++) {
92 ff
[i
].base
= G_CREATE(gg
);
94 if (MP_NEGP(f
[i
].exp
))
95 G_INV(gg
, ff
[i
].base
, f
[i
].base
);
97 G_COPY(gg
, ff
[i
].base
, f
[i
].base
);
98 if (f
[i
].exp
->f
& MP_BURN
)
99 G_BURN(gg
, ff
[i
].base
);
100 ff
[i
].exp
= f
[i
].exp
;
102 G_COPY(gg
, d
, gg
->i
);
104 for (i
= 0; i
< n
; i
++)
105 G_DESTROY(gg
, ff
[i
].base
);
109 /*----- That's all, folks -------------------------------------------------*/